The Piscataqua is a tidal estuary fed chiefly by the Salmon Falls, Lamprey and Exeter rivers.
LAMPREY, a fish belonging to the family Petromyzontidae (from r rpos and Ww, literally, stone-suckers), which with the hag-fishes or Myxinidae forms a distinct subclass of fishes, the Cyclostomata, distinguished by the low organization of their skeleton, which is cartilaginous, without vertebral segmentation, without ribs or real jaws, and without limbs.
Mackerel, cod, pollack and flat-fishes are the kinds most frequently attacked by them in the sea; of river-fish the migratory Salmonidae and the shad are sometimes found with the marks of the teeth of the lamprey, or with the fish actually attached to them.
The first two are migratory, entering rivers in the spring to spawn; of the river-lamprey, however, specimens are met with in fresh water all the year round.
In North America about ten species of lamprey occur, while in South America and Australasia still others are found.
Lampreys, especially the sea-lamprey, are esteemed as food, formerly more so than at present; but their flesh is not easy of digestion.
The species of greatest use is the river-lamprey, which as bait is preferred to all others in the cod and turbot fisheries of the North Sea.
Woollen cloth, machinery and spirits are manufactured; there is an extensive salt-mine in the neighbouring Zillenberg; the salmon and lamprey fisheries are important; and a fair amount of commercial activity is maintained.
- /, ,,;- the adult lamprey among the Cyclostomata the liver underFIG.
(After Rathke, slightly altered.) m, Mouth appearing as an elongated slit when relaxed (as in the lamprey); p, perforated pharynx; e, endostyle; g, gonads; 1, liver; at, level of atriopore; intestine; an, anus.